Recently need for more efficient usage of wireless communication resources has brought out more scenarios of spectrum sharing. In one conventional spectrum sharing scenario, primary users communicate with each other in a first frequency band based on a first communication technology, secondary users communicate with each other in a second frequency band based on a second communication technology, where the first frequency band and the second frequency band partly overlap with each other. To secure communications of the primary users, the secondary users will reduce their transmission power once they perceive the existence of a primary user.